This fix is the first one you should try and nearly always works. Thanks to Ashe for writing it and morpheus2matrix for providing it. Open includes/sessions.php using a text/code editor such as Wordpad, and find the following code (line 152).

################################################################# ## MOD Title: Guest Sessions MOD## MOD Version: 0.04## MOD Author: CyberAlien <no@public_email> (Vjacheslav Trushkin) http://www.phpbbstyles.com## MOD Description: ## This mod removes session id for guests from url and this way## guests who don't have cookies like different robots will use## correct urls. It can be used to allow googlebot and other## search engines to spider your forum correctly.#### Installation Level: Easy## Installation Time: 1-2 Minutes## Files To Edit (1): includes/sessions.php############################################################## ## For Security Purposes, Please Check: http://www.phpbb.com/mods/ for the ## latest version of this MOD. Downloading this MOD from other sites could cause malicious code ## to enter into your phpBB Forum. As such, phpBB will not offer support for MOD's not offered ## in our MOD-Database, located at: http://www.phpbb.com/mods/ ############################################################## ## Before Adding This MOD To Your Forum, You Should Back Up All Files Related To This MOD ##############################################################

################################################################# ## MOD Title: Guest Sessions MOD## MOD Version: 0.04## MOD Author: CyberAlien <no@public_email> (Vjacheslav Trushkin) http://www.phpbbstyles.com## MOD Description: ## This mod removes session id for guests from url and this way## guests who don't have cookies like different robots will use## correct urls. It can be used to allow googlebot and other## search engines to spider your forum correctly.#### Installation Level: Easy## Installation Time: 1-2 Minutes## Files To Edit (1): includes/sessions.php############################################################## ## For Security Purposes, Please Check: http://www.phpbb.com/mods/ for the ## latest version of this MOD. Downloading this MOD from other sites could cause malicious code ## to enter into your phpBB Forum. As such, phpBB will not offer support for MOD's not offered ## in our MOD-Database, located at: http://www.phpbb.com/mods/ ############################################################## ## Before Adding This MOD To Your Forum, You Should Back Up All Files Related To This MOD ##############################################################